The Effect of SnO2-Sb Interlayer on the Physicochemical Properties of Electrodeposited Ti/PbO2 Electrodes

Lead dioxide (PbO₂) coated titanium (Ti) anodes have been extensively investigated owing to its well-proven advantages such as low cost compared to those based on precious metals, good electrical conductivity that is comparable to metals, ease of preparation, high oxygen evolution potential and good stability in corrosive media [1]. However, traditional PbO₂ deposited Ti electrodes suffer from poor adhesion problem, due to the formation of an insulating TiO₂ between the coating and Ti substrate during anodic polarization in aqueous media. SnO₂, as an interlayer, has been recently applied on Ti substrate to prepare PbO₂anodes to improve the stability and electro-catalytic activity. The application of such doped interlayer is reported to have increased electrode’s chemical stability, enhanced electro-catalytic activity and greatly prolonged service life of the electrodes [2, 3,4].

In the present work, we explored the electro-deposition process of PbO₂ on the Ti substrate with a Sb-doped SnO₂ interlayer, from a traditional acidic nitrate solution. By varying electro-deposition temperature, time and current density, we are able to synthesise PbO₂ coatings with various morphologies (as can be seen in Figure 1.), microstructures and crystallite sizes. The surface morphology and phase structure were characterized by SEM and XRD. Voltammetric studies were performed using a conventional three-electrode cell system and a CHI604D (Chenhua, Shanghai) electrochemical workstation. It is found that an interlayer SnO₂-Sb on Ti substrate can significantly promote the electro-deposition of PbO₂ coatings. The preliminary results revealed that the electrochemical performance of deposited PbO₂ largely depends on their morphologies and microstructures. The deposition temperature, deposition time and current density affect the PbO₂ coatings in a synergic manner.

It is our purpose to establish a correlation between electrolyte temperature, deposition time, current density and phase structure, morphological features on the Ti/SnO₂-Sb substrate. This information may shed light on a further understanding of electro-crystallisation and also provide a perspective on further possible improvement of the electrochemical performance of PbO₂coatings in terms of service lifetime and electro-catalytic activity.

Keywords: Lead dioxide; Electro-deposition; Surface characterisation; SnO₂ interlayer

References

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[2] S. Song, L. Zhan, Z. He, L. Lin, J. Tu, Z. Zhang, J. Chen, L. Xu, J. Hazard. Mater., 175 (2010) 614.

[3] Y. Wang, B. Gu, W. Xu, L. Lu, Rare Metal Mat. Eng., 36 (2007) 874.

[4] H. An, Q. Li, D. Tao, H. Cui, X. Xu, L. Ding, L. Sun, J. Zhai, 258 (2011) 218.